The occurrence of postoperative hemorrhage (POH) following thyroidectomy is a rare but serious complication. The frequency is rather low, varying from 0.5 to 2.8%, rarely more, although a rate of 6.5% has been reported. Given its early onset, a HPO leads to the formation of a hematoma in the empty thyroid compartment, which can be suffocating and lead to death, particularly at night.
Its prevention is therefore essential, in particular through the analysis of risk factors. Bilateral surgery, for recurrence, cancer, plunging goiter and that for Graves’ disease, are considered to be more risky. It is the same for the male sex while the majority of thyroidectomies concern the fairer sex. But these variables, although they must be taken into account, cannot be modified.
It is not the same for the role of the surgeon and that of variations in blood pressure, particularly systolic (SBP). A team from Vienna (Austria) reports its results based on a large database collected prospectively over more than 40 years (1).
A series of more than 40,000 thyroidectomies
The study included 43,360 thyroidectomies performed consecutively in this department between 1979 and 2022, including demographic data, medical history, thyroid pathology, operative techniques and complications. Patients aged less than 18 years, operated for thyroidectomy with associated parathyroidectomy, or with incomplete data were excluded from the study.
Particular attention was paid to variations in systolic blood pressure (SBP) during and after surgery. Patients requiring reoperation for HPO were compared to patients matched according to age and severity of the procedure.
Reoperation for HPO was defined by the finding of visible neck swelling associated with signs of upper airway obstruction and/or a drainage volume greater than 150 ml when a drain was present. The cause of the bleeding (arterial and/or venous) was specified. The surgeons in this department were highly specialized and the majority of them had more than 500 thyroidectomies to their credit.
Anticoagulants and antiplatelet agents were stopped between 2 and 10 days before the procedure and a switch to low molecular weight heparin was carried out if necessary. Only aspirin was maintained in patients whose vascular situation (notably those with coronary stents) made it imperative.
Note that in their practice, the authors carried out prevention of deep vein thrombosis with low molecular weight heparin until discharge from hospital. This prevention is not systematically recommended in France by the SFAR in thyroid surgery except in high-risk areas or major cancer surgery (2).
Until 2011, post-operative drainage was systematically implemented. Postoperative monitoring was particularly close with hourly measurement of hemodynamic parameters and neck circumference during the first 12 hours.
In case of POH, the choice of hemostasis was left to the discretion of the operators whether it involved ligations, the use of bipolar coagulation or thermofusion (Ligasure, Medtronic Ltd, UK). In addition to a risk factor analysis, a subanalysis of perioperative SBP values was performed in 26 patients with POH and 26 controls, based on the hypothesis that a targeted pharmacological increase in SBP could help identify hidden sources of bleeding.
From 2013, SBP monitoring was implemented. Throughout the procedure, the anesthetic team had to maintain a SBP >150 mmHg by injection on demand of neosynephrine (or etilefrine more rarely), particularly during the review of hemostasis at the end of the procedure before closure. . After this review, the protocol included a Valsalva maneuver (with positive end-expiratory pressure of at least 40 mmHg) to detect venous bleeding.
Less than 2% of those operated on
In the cohort studied over more than 40 years, 1.6% (707 patients) of patients presented with HPO requiring surgical revision. This rate decreased from 2009, going from 2.38% (2004-2008) to 1.09% (2019-2022). Among the risk factors identified were age, with each additional year slightly increasing the risk (RR 1.017), and gender, with men having a 62% higher risk than women.
As already reported, Graves’ disease (RR 1.515) and surgeries for recurrent nodules or benign goiters (RR 1.693) were associated with higher levels of HPO, while surgeries for euthyroid goiter were not. Bilateral and complex surgeries increased the risk of POH (RR 1.704 for bilateral thyroidectomies).
More specifically to this study, patients who presented with HPO had lower intraoperative SBP values (median 100 mmHg) but higher postoperative values (median 150 mmHg) compared to controls (respectively 120 mmHg and 130 mmHg). Since the establishment of the protocol, the pharmacological elevation of SBP to 150 mmHg before closure had made it possible to detect latent sources of bleeding, mainly arterial.
Concerning the influence and role of the surgeon, the observations corroborated a rarely published impression, namely that HPO rates varied considerably between surgeons, with risks increased up to 2.8 times between practitioners (1.1 at 2.8%), hence the importance of training and experience. However, there was no significant difference regarding the concordance or not of gender between surgeon and patient.
As PHOs were mainly observed more than six hours after surgery (42% of cases), this result may call into question the feasibility of ambulatory thyroidectomies as is now commonly practiced. In these cases, the bleeding was mainly of arterial origin. The study did not highlight any particular benefit of thermofusion.
Overall, the results of this study are significant, particularly in terms of the age of the cohort and its volume. They show an HPO rate of 1.6% in a specialized department, decreasing over recent years. Elevation of operative SBP appears to be an effective strategy to prevent POH by making it possible to identify latent bleeding.
Collaboration with anesthesiologists is emphasized for maintaining adequate intraoperative SBP and managing postoperative SBP increases. The authors recommend pharmacological augmentation of SBP and careful inspection of the surgical field before closure, although further studies are needed to support this conclusion. They also insist on raising operator awareness of effective hemostasis techniques and the risks associated with inadequate SBP values.
